We plan to determine the local immune response to selected antigens of V. cholerae and enterotoxigenic E. coli in humans exposed to these antigens either through naturally occurring diarrheal disease or through immunization. We will use samples obtained from the intestinal lavage procedure as well as samples of saliva, breast milk, and serum. We will then use ELISA methods to measure anti cholera toxin and anti LPS antibodies. Using these methods we plan to characterize the magnitude and duration of the local immune response in order to maximize this response from immunization with new oral cholera vaccines. Secondarily we hope to find correlations between antibody responses in other samples and the intestinal sample which will allow us to use these other specimens as proxy measurement of the intestinal immune response.